Kant has long been taxed with an inability to explain the detailed normative content of our lives by making universalizability the sole arbiter of our values. Korsgaard addresses one form of this critique by defending a Kantian theory amended by a seemingly attractive conception of practical identities. Identities are dependent on the contingent circumstances of each person's world. Hence, obligations issuing from them differ from Kantian moral obligations in not applying to all persons. Still, Korsgaard takes Kantian autonomy to mean the normativity of all obligations is rooted in universalizability. The wealth of values informing our lives is thus said to be accommodated within a Kantian framework.After briefly explaining Korsgaard’s understanding of practical identities and their role in her reformation of Kant's moral philosophy, I argue that she gives an inadequate explanation of how the obligations that arise from a person’s practical identities derive their authority from the person's will. I then consider how her position might be developed to meet this objection in accordance with her allegiance to “constructivism” and I argue that the epistemic commitments of people’s actual identities makes it unlikely that such a development could preserve Kantian autonomy as she interprets it